5-Formylhonokiol exerts anti-angiogenesis activity via inactivating the ERK signaling pathway

Our previous report has demonstrated that 5-formylhonokiol (FH), a derivative of honokiol (HK), exerts more potent anti-proliferative activities than honokiol in several tumor cell lines. In present study, we first explored the antiangiogenic activities of 5-formylhonokiol on proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs) for the first time in vitro. Then we investigated the in vivo antiangiogenic effect of 5-formylhonokiol on zebrafish angiogenesis model. In order to clarify the underlying molecular mechanism of 5-formylhonokiol, we investigated the signaling pathway involved in controlling the angiogenesis process by western blotting assay. Wound-healing results showed that 5-formylhonokiol significantly and dose-dependently inhibited migration of cultured human umbilical vein enthothelial cells. The invasiveness of HUVEC cells was also effectively suppressed at a low concentration of 5-formylhonokiol in the transwell assay. Further F-actin imaging revealed that inhibitory effect of 5-formylhonokiol on invasion may partly contribute to the disruption of assembling stress fiber. Tube formation assay, which is associated with endothelial cells migration, further confirmed the anti-angiogenesis effect of 5-formylhonokiol. In in vivo zebrafish angiogenesis model, we found that 5-formylhonokiol dose-dependently inhibited angiogenesis. Furthermore, western blotting showed that 5-formylhonokiol significantly down-regulated extracellular signal-regulated kinase (ERK) expression and inhibited the phosphorylation of ERK but not affecting the total protein kinase B (Akt) expression and related phosphorylation, suggesting that 5-formylhonokiol might exert anti-angiogenesis capacity via down-regulation of the ERK signal pathway. Taken together, these data suggested that 5-formylhonokiol might be a viable drug candidate in antiangiogenesis and anticancer therapies.

Role of P38 MAPK activation in glucose-induced microvascular hyperpermeability of rats / 基础医学与临床

Objective To study the role of P38 mitogen-activated protein kinase(P38 MAPK) activation in high level glucose-induced microvascular hyperpermeability.Methods Rats were induced to diabetis by intraperitoneal injection of streptozotocin(STZ).The rats were divided into 5 groups,including normal,diabetes,control,MKK6b(A) and MKK6b(E) groups.The permeability coefficient to albumin(Pa) was measured in venules of in vivo mesenterium using a fluorescence ratio technique;Morphological changes of microvascular endothelial cell were monitored by observing fluorescence of F-actin stained with rhodamine-phalloidin.Results The permeability of diabetic rats was obviously increased.The activation of P38 MAPK by MKK6b(E) could increase microvascular permeability in normal rats,and the inhibition of P38 MAPK by MKK6b(A) could inhibit hyperpermeability of diabetic rats.Conclusion The activation of P38 MAPK induced by hyperglycemia may play a role in diabetic microvascular hyperpermeability.